Screens of current mobile phones are getting larger as the mobile phones become thinner and thinner. Due to the complex structure of the traditional moving coil receiver, it is difficult to fit such receiver in a thinner mobile phone. Full-screen (i.e. narrow bezel) mobile phones generally use a piezoelectric receiver for the purposes of miniaturization and thinness, and use bone conduction technology for sound transmission. However, piezoelectric receivers using bone conduction technology are generally expensive.